Bushings are assembled between inside sidebars, forming blocks or bushing links. Pins are extended through outside sidebars and bushings in adjacent bushing links, and are fixed in opposite outside sidebars, forming pin links, which alternate with bushing links.
Relative movement of the chain links occurs as relative rotation between the fixed bushings and the fixed pins. Wear occurring in the pins and bushings results in chain elongation. Excess wear and elongation require chain replacement. Lubrication of the pin-bushing interfaces increases chain life. Debris and abrasive dust in the pin-bushing rotation interfaces increase wear and decrease chain life.
Pin and bushing chains are lubricated with grease and are sealed to extend life of the chain by lubricating the pin-bushing interfaces, preventing egress of grease and preventing ingress of particles between the pins and bushings. Sealing the pin bushing interface reduces or prevents wear and extends useful chain life.
Sealing of the lubrication prevents outward migration of grease and inward migration of particles. Seals have been provided at ends of bushings between inside and outside sidebars. Some pins have grease fittings and channels to add lubricant.
Needs exist for improved seals.